[es6] Consistently use %_GetSuperConstructor to implement super calls.

src/full-codegen/mips64/full-codegen-mips64.cc

Index: src/full-codegen/mips64/full-codegen-mips64.cc
diff --git a/src/full-codegen/mips64/full-codegen-mips64.cc b/src/full-codegen/mips64/full-codegen-mips64.cc
index ed41fcdb828e114d61716a5dd14f4fe0a7593201..bda85f52367de2128bcdb342c89283ce8250d4e5 100644
--- a/src/full-codegen/mips64/full-codegen-mips64.cc
+++ b/src/full-codegen/mips64/full-codegen-mips64.cc
@@ -3009,8 +3009,15 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
       expr->expression()->AsSuperCallReference();
   DCHECK_NOT_NULL(super_call_ref);
 
-  EmitLoadSuperConstructor(super_call_ref);
-  __ push(result_register());
+  // Push the super constructor target on the stack (may be null,
+  // but the Construct builtin can deal with that properly).
+  VisitForAccumulatorValue(super_call_ref->this_function_var());
+  __ AssertFunction(result_register());
+  __ ld(result_register(),
+        FieldMemOperand(result_register(), HeapObject::kMapOffset));
+  __ ld(result_register(),
+        FieldMemOperand(result_register(), Map::kPrototypeOffset));
+  __ Push(result_register());
 
   // Push the arguments ("left-to-right") on the stack.
   ZoneList<Expression*>* args = expr->arguments();